Cardiac Cycle

Question 1

opening and closing of the valves depends on what?

Answer 1

development of pressure gradients acoss the valve

Question 2

what are the artioventricular valves

Answer 2

Mitral and tricuspid

Question 3

mitral valve

Answer 3

separates left atrium and left ventricle

Question 4

tricuspid valve

Answer 4

separates the right atrium and right ventricle

Question 5

what atteches the lower side of AV valves to papillary muscles

Answer 5

chordae tendineae

Question 6

when does papillary muscle contraction occur? Why?

Answer 6

during ventricular contraction - prevents AV valves from buldging back into the atrial chambers

Question 7

semilunar valves

Answer 7

Aortic valve and pulmonic valve

Question 8

aortic valve

Answer 8

separates the left ventricle and the aorta

Question 9

pulmonic valve

Answer 9

separates the right ventricle from the pulmonary artery

Question 10

Sinus of Valsalva

Answer 10

prevents aotric valve leaflets from obstructing the coronary ostia during ejetcion

Question 11

Which valves snap closed with greater force? Why?

Answer 11

Semilunar valves (aortic and pulmonary) - due to greater pressures

Question 12

Systole

Answer 12

1/3 of cardiac cycle period of cardiac contraction - Mitral valve closure to aortic valve closure

Question 13

Diastole

Answer 13

2/3 of cardiac cycle period of cardiac relaxation - from aortic valve closure to mitral valve closure

Question 14

relationship between diastole and heart rate

Answer 14

at higher heart rates we spend less time in diastole - shifts to 50/50 systole/diastole

Question 15

Systole begins at

Answer 15

mitral valve closure

Question 16

Ejection begins at

Answer 16

aortic valve opening

Question 17

Ejection ends at

Answer 17

aortic valve closure

Question 18

Diastole begins at

Answer 18

aortic valve closure

Question 19

Ventricular filling begins at

Answer 19

mitral valve opening

Question 20

Phases of ventricular systole

Answer 20

1.) isovolumic contraction 2.) Rapid ejection 3.) reduced ejection

Question 21

isovolumic contraction

Answer 21

since both mitral and aortic valves are closed ventricular blood volume does not change but muscle contraction causes ventricular pressure to rise

Question 22

Rapid ejection

Answer 22

immediately after aortic valve opens blood is expelled from the ventricle more rapidly than it leave the aorta causing both ventricular and aortic pressures to rise.

Question 23

Reduced ejection

Answer 23

last 60% of the ejection period - blood leaves the left ventricle more slowly and aortic and ventricular pressures fall

Question 24

phases of ventricular diastole

Answer 24

1.) Prodiastole 2.) Isovolumic relaxation 3.) rapid filling 4.) Diastasis 5.) Atrial systole/ Atrial kick

Question 25

prodiastole

Answer 25

short period after ventricles begin to relax during which the aortic valve is still open

Question 26

isovolumic relaxation

Answer 26

both aortic and mitral valves are closed so ventricular blood volume is consistant. As ventricles relax the pressure drops. This phase ends whe the ventricular presssure falls below atrial pressure and the mitral valve opens

Question 27

Rapid filling

Answer 27

70% of the filling from left atrium

Question 28

diastasis

Answer 28

second 1/3 of filling period

Question 29

Atrial systole/Atrial kick

Answer 29

last 1/3 of filling period 30% of filling

Question 30

what determines aortic pressure

Answer 30

elastic distention of the aorta - distention is dtermined by the relative rate at which blood is pumped into the airta and the rate at which it runs off into the periphery

Question 31

atrial “a” wave

Answer 31

atrial pressure increase seen during atrial contraction just before the AV valve closes

Question 32

atrial “c” wave

Answer 32

atrial pressure increase that occurs during ventricular contraction when the AV valve bulge back into the atria

Question 33

atrial “v” wave

Answer 33

atrial pressure increas which occurs as venous return fills the atrium while the AV valve is shut. Peak occurs just before mitral valve opening

Question 34

atrial “x-descent”

Answer 34

Systolic collapse. Valley following the c-wave

Question 35

atrail “y descent”

Answer 35

Diastolic collapse. Valley following the V wave.

Question 36

atrial contraction contributes to what percentage of ventricular filling

Answer 36

30% - atrial contraction is not essential to maintain normal heart function under RESTING conditions. Can lead to significant impairment under conditions of high demand (eg: exercise)

Question 37

1st heart soud

Answer 37

mitral and tricusoud closeure. Signals the beginning of systole

Question 38

2nd heart sound

Answer 38

aortic and pulmonic closure. Signal the beginning of clinical diastole

Question 39

3rd heart sound

Answer 39

occurs sometime between middle or end of rapid ventricular fillling. Generally only heard in young normal individuals or in pathological states

Question 40

4th heart sound

Answer 40

Atrial sound. Associated with atrial contraction at the end of ventricular diastole. Generally not audible

Question 41

Valve sequence

Answer 41

mitral closes, tricuspid closes, pulmonic opens, aortic opens, aortic closes, pulmonic closes, tricuspid opens, mitral opens.

Question 42

why does the mitral valve close before the tricuspid valve

Answer 42

LV contraction precedes RV cintraction

Question 43

why does pulmonic valve open before the aortic valve

Answer 43

right heart afterload is lower

Question 44

why does aortic valve close before pulmonic valve

Answer 44

higher aortic pressure

Question 45

what causes splitting of the second heart sound

Answer 45

inspiration - it accentuates the differences between the right and left sides. Aortic closure is heard before pulmonary closure

Question 46

QRS occurs just before what in the cariac cycle

Answer 46

just before isovolumic contraction